1. Technical Field of the Invention
The present invention relates to semiconductor devices and manufacturing methods thereof, and more particularly, relates to a semiconductor device and a manufacturing method thereof, in which pad peeling of a bonding pad portion is suppressed.
2. Description of the Related Art
FIG. 16 is a cross-sectional view showing a conventional semiconductor device. This semiconductor device has bonding pad portions.
On a silicon substrate not shown in the figure, an insulating film 101 is formed, and on this insulating film 101, a Ti film 102 is deposited by sputtering, followed by deposition of a TiN film 103 thereon by sputtering. A barrier metal layer 104 made of the Ti film 102 and the TiN film 103 is formed on the insulating film 101.
Next, on this barrier metal 104, a first Al alloy film 105 is formed by sputtering, and an antireflection film 106 made of a TiN film is then formed thereon. Subsequently, the antireflection film 106, the first Al alloy film 105, and the barrier metal layer 104 are patterned. Accordingly, on the insulating film 101, first Al alloy wires 107a and 107b are formed.
Next, an interlayer insulating film 108 made of an oxide film is formed over the first Al alloy wires 107a and 107b. Subsequently, by etching this interlayer insulating film 108, via holes are formed therein at positions located on the first Al alloy wires 107a and 107b. Next, after a Ti film 112 is deposited inside the via holes and on the interlayer insulating film by sputtering, a TiN film 113 is formed on this Ti film 112 by sputtering. As described above, inside the via holes and on the interlayer insulating film 108, a barrier metal layer 114 made of the Ti film 112 and the TiN film 113 is formed.
Then, on the barrier metal layer 114 and inside the via holes, a W film is deposited by a CVD (chemical vapor deposition) method. After the W film present on the interlayer insulating film 108 is removed by etching (etch-back), a W plug 109 is buried in each via hole formed in the interlayer insulating film 108.
Next, over the entire surface including the W plugs 109, a second Al alloy film 115 is deposited by sputtering, and an antireflection film 116 made of a TiN film is formed thereon. The antireflection film 116, the second Al alloy film 115, and the barrier metal layer 114 are then patterned. Accordingly, on the interlayer insulating film 108, a bonding pad portion 117a and a second Al alloy wire 117b are formed. The bonding pad portion 117a is electrically connected to the first Al alloy wire 107a via the W plug 109, and the second Al alloy wire 117b is electrically connected to the first Al alloy wire 107b via the W plug 109.
Subsequently, over the entire surface including the bonding pad portion 117a and the second Al alloy wire 117b, a passivation film 110 made of a silicon nitride film or the like is deposited by a CVD method. Next, by etching the passivation film 110, an opening portion is formed in the passivation film at a position located on the bonding pad portion 117a. A polyimide film 111 is then formed on the passivation film 110, and an opening portion is formed in this polyimide film 111 at a position located on the aforementioned opening portion. As described above, a pad opening portion for bonding is formed for the bonding pad portion 117a. Through this pad opening portion, the bonding pad portion 117a is exposed.
When a wire is bonded to the bonding pad portion 117a, a stress is applied thereto which is generated by this bonding connection, and due to this stress, peeling of the bonding pad portion 117a may occur in some cases. This peeling of the bonding pad portion 117a is caused by peeling which occurs at the interface between the Ti film 112 of the barrier metal layer and the interlayer insulating film (oxide film) 108. The reason for this is that since a vulnerable alloy layer which has poor stress resistance is formed at the interface between the oxide layer and the Ti film 112, when bonding connection is performed for the bonding pad portion 117a, this vulnerable layer is destroyed by a stress generated in the bonding connection. As a result, peeling of the bonding pad portion occurs.
In consideration of the situations described above, the present invention was made, and an object of the present invention is to provide a semiconductor device and a manufacturing method thereof, in which peeling of the bonding pad portion is suppressed.